Energy Recovery Apparatus with Changeable Nozzles, For Use in a Refrigeration System

ABSTRACT

An energy recovery apparatus adapted for use in a refrigeration system comprises a housing, a turbine, a first nozzle, and a second nozzle. The housing has a nozzle receiving opening and a discharge port. The first and second nozzles are each operably connectable to the housing in alignment with the nozzle receiving opening. Each nozzle is adapted to expand refrigerant and discharge it in a liquid-vapor state. The size or shape of the second nozzle is different from the size or shape of the first nozzle to enable a user to selectively choose one of the first and second nozzles for operable connection to the housing. The user may make the choice that accomplishes the better refrigerant flow characteristics when the passageway of the chosen nozzle is within the refrigeration system.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

APPENDIX

Not Applicable.

BACKGROUND OF THE INVENTION Field of the Invention

This invention pertains to an energy recovery apparatus for use in a refrigeration system.

SUMMARY OF THE INVENTION

One aspect of the present invention is an energy recovery apparatus adapted for use in a refrigeration system. The refrigeration system comprises a first heat exchanger, a compressor and a second heat exchanger. The refrigeration system is configured to circulate refrigerant along a flow path such that the refrigerant flows from the first heat exchanger to the compressor, and from the compressor to the second heat exchanger, and from the second heat exchanger to the first heat exchanger. The energy recovery apparatus is adapted and configured to be in the flow path operatively between the second heat exchanger and the first heat exchanger. The energy recovery apparatus comprises a housing, a turbine, a first nozzle, and a second nozzle. The housing has a nozzle receiving opening and a discharge port. The turbine is within the housing. The turbine is adapted to be driven by refrigerant passing through the nozzle receiving opening. The first nozzle comprises a first nozzle body having a first conduit region. The first conduit region defines a first passageway. The first passageway has a discharge end. The first nozzle is operably connectable to the housing in a position in which the first passageway aligns with the nozzle receiving opening. The first nozzle is adapted and configured to expand refrigerant passing through the first nozzle and to discharge the refrigerant from the discharge end of the first passageway in a liquid-vapor state with a liquid component and a vapor component. The second nozzle comprises a second nozzle body having a second conduit region. The second conduit region defines a second passageway. The second passageway has a discharge end. The second nozzle is operably connectable to the housing in a position in which the second passageway aligns with the nozzle receiving opening. The second nozzle is adapted and configured to expand refrigerant passing through the second nozzle and to discharge the refrigerant from the discharge end of the second passageway in a liquid-vapor state with a liquid component and a vapor component. The size or shape of the second passageway of the second nozzle is different from the size or shape of the first passageway of the first nozzle to enable a user to selectively choose one of the first and second nozzles for operable connection to the housing, whereby the user may make the choice that accomplishes the better refrigerant flow characteristics when the passageway of the chosen nozzle is in the flow path of the refrigeration system. The discharge port is adapted to permit refrigerant to flow out of the energy recovery apparatus. The discharge port of the energy recovery apparatus is downstream of the turbine.

Another aspect of the present invention is a method comprising providing to a person an energy recovery apparatus sub-assembly, a first nozzle, and a second nozzle. The energy recovery apparatus sub-assembly is adapted for use in a refrigeration system. The refrigeration system comprises a first heat exchanger, a compressor and a second heat exchanger. The refrigeration system is configured to circulate refrigerant along a flow path such that the refrigerant flows from the first heat exchanger to the compressor, and from the compressor to the second heat exchanger, and from the second heat exchanger to the first heat exchanger. The energy recovery apparatus sub-assembly is adapted and configured to be in the flow path operatively between the second heat exchanger and the first heat exchanger. The energy recovery apparatus sub-assembly comprises a housing, a turbine, and a generator. The housing has a nozzle receiving opening and a discharge port. The turbine and the generator are within the housing. The turbine is adapted to be driven by refrigerant passing through the nozzle receiving opening. The generator is coupled to the turbine and adapted to be driven by the turbine. The generator is configured to produce electricity as a result of the turbine being driven by refrigerant passing through the nozzle receiving opening. The discharge port is adapted to permit refrigerant to flow out of the energy recovery apparatus. The discharge port of the energy recovery apparatus is downstream of the turbine. The first nozzle comprises a first nozzle body having a first conduit region. The first conduit region defines a first passageway. The first passageway has a discharge end. The first nozzle is operably connectable to the housing in a position in which the first passageway aligns with the nozzle receiving opening. The first nozzle is adapted and configured to expand refrigerant passing through the first nozzle and to discharge the refrigerant from the discharge end of the first passageway in a liquid-vapor state with a liquid component and a vapor component. The second nozzle comprises a second nozzle body having a second conduit region. The second conduit region defines a second passageway. The second passageway has a discharge end. The second nozzle is operably connectable to the housing in a position in which the second passageway aligns with the nozzle receiving opening. The second nozzle is adapted and configured to expand refrigerant passing through the second nozzle and to discharge the refrigerant from the discharge end of the second passageway in a liquid-vapor state with a liquid component and a vapor component. The size or shape of the second passageway of the second nozzle is different from the size or shape of the first passageway of the first nozzle to enable a user to selectively choose one of the first and second nozzles for operable connection to the housing, whereby the user may make the choice that accomplishes the better refrigerant flow characteristics when the passageway of the chosen nozzle is in the flow path of the refrigeration system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of an embodiment of an energy recovery apparatus of the present invention, the energy recovery apparatus including an energy recovery apparatus sub-assembly and changeable first and second nozzles.

FIG. 2 is a perspective view of the energy recovery apparatus sub-assembly of FIG. 1 with the first nozzle attached to the sub-assembly.

FIG. 3 is a schematic view of an embodiment of a refrigeration system of the present invention, the refrigeration system including the sub-assembly and first nozzle of FIG. 2.

FIG. 4 is a top plan view of the energy recovery apparatus sub-assembly and first nozzle of FIG. 2.

FIG. 5 is a cross-sectional view taken along the plane of line 5-5 of FIG. 4.

FIG. 6 is a front elevational view of the energy recovery apparatus sub-assembly and first nozzle of FIGS. 2 and 4.

FIG. 7 is a cross-sectional view taken along the plane of line 7-7 of FIG. 6.

FIG. 8 is a cross-sectional view of the second nozzle of FIG. 1.

Reference numerals in the written specification and in the drawing figures indicate corresponding items.

DETAILED DESCRIPTION

An embodiment of an energy recovery apparatus of the present invention is indicated generally by reference numeral 20 in FIG. 1. The energy recovery apparatus 20 includes an energy recovery apparatus sub-assembly, generally indicated at 22, and changeable first and second nozzles 24, 26, respectively. As used herein, the term “energy recovery apparatus” sometimes means the energy recovery apparatus sub-assembly plus the changeable nozzles. But it is to be understood that when the energy recovery apparatus is described as being in the flow path of a refrigeration system, only one of the nozzles is in the flow path, and the energy recovery apparatus includes only the sub-assembly and the attached nozzle.

Referring to FIG. 3, an embodiment of a refrigeration system of the present invention is indicated generally by reference numeral 30. The refrigeration system 30 comprises a first heat exchanger 32, a compressor 34, a second heat exchanger 36, and the energy recovery apparatus 20 (i.e., the energy recovery apparatus sub-assembly 22 and the first nozzle 24. The refrigeration system 30 is configured to circulate refrigerant along a flow path such that the refrigerant flows from the first heat exchanger 32 to the compressor 34, and from the compressor to the second heat exchanger 36, and from the second heat exchanger to the energy recovery apparatus 20, and from the energy recovery apparatus to the first heat exchanger. The first heat exchanger 32 of the present embodiment is an evaporator. The second heat exchanger 36 of the present embodiment is a condenser. It is to be understood, however, that the second heat exchanger could comprise a gas cooler of a transcritical refrigeration system.

Referring to FIG. 5, the energy recovery apparatus sub-assembly 22 is basically comprised of a housing 40, a turbine 42 and a generator 44. The turbine 42 and generator 44 are preferably contained in the housing. The housing 40 preferably comprises two parts. A first, center housing part 46 has an interior that supports a bearing assembly 48. The center part 46 is attached to a second, side wall part 48 of the housing. The side wall 50 is preferably generally cylindrical in shape and extends around an interior volume of the housing 40. The center housing part 46 also includes a hollow center column 52. The interior of the center column 52 supports a second bearing assembly 54. The top of the housing 40 preferably has an outlet opening (or discharge port) 58 that is the outlet for the refrigerant passing through the e energy recovery apparatus sub-assembly 22. The discharge port 58 of the energy recovery apparatus 24 is downstream of the turbine 42. The housing 40, the turbine 42, and the generator 44 are arranged and configured such that refrigerant passing through the energy recovery apparatus cools and lubricates the generator.

Except for the nozzle changeability, the energy recovery apparatus sub-assembly 22 combined with either of the first or second nozzles 24, 26 are similar to the energy recovery apparatus described in co-pending U.S. patent application Ser. No. 13/948,942 filed Jul. 23, 2013 (incorporated herein by reference).

Referring to FIG. 7, the first nozzle 24 comprises a first nozzle body 24 a having a first conduit region 60 defining a first passageway 62. The first nozzle further comprises a first necked-down region 64. The first passageway 62 is downstream of the first necked-down region 64. The first necked down region 64 and the first passageway 62 are adapted to constitute portions of the flow path when the first nozzle 24 is connected to the energy recovery apparatus sub-assembly 22 and within the refrigeration system 30. The first passageway 62 has an upstream cross-section, indicated by the dash line 66, a downstream cross-section, indicated by the dash line 68, a first passageway length extending from the upstream cross-section 66 of the first passageway to the downstream cross-section 78 of the first passageway, and a discharge end 70. The downstream cross-section 78 of the first passageway 62 is closer to the discharge end 70 of the first passageway 62 than to the upstream cross section 66 of the first passageway. The first nozzle 24 is adapted and configured such that when the first nozzle is connected to the energy recovery apparatus sub-assembly 22 and within the refrigeration system 30, refrigerant is expanded as it passes through the first nozzle and is discharged from the discharge end 70 of the first passageway 62 in a liquid-vapor state with a liquid component and a vapor component.

Referring to FIG. 8, the second nozzle 26 comprises a second nozzle body 26 a having a second conduit region 72 defining a second passageway 74. The second nozzle 26 further comprises a second necked-down region 76. The second passageway 74 is downstream of the second necked-down region 76. The second necked-down region 76 and the second passageway 74 are adapted to constitute portions of the flow path when the second nozzle 22 is connected to the energy recovery apparatus sub-assembly 22 and within the refrigeration system 30. The second passageway 74 has an upstream cross-section, indicated by the dash line 78, a downstream cross-section, indicated by the dash line 80, a second passageway length extending from the upstream cross-section 78 of the second passageway 74 to the downstream cross-section 80 of the second passageway, and a discharge end 82. The downstream cross-section 80 of the second passageway 74 is closer to the discharge end 82 of the second passageway than to the upstream cross section 78 of the second passageway. The second nozzle 26 is adapted and configured such that when the second nozzle is connected to the energy recovery apparatus sub-assembly 22 and within the refrigeration system 30, refrigerant is expanded as it passes through the second nozzle and is discharged from the discharge end 82 of the second passageway in a liquid-vapor state with a liquid component and a vapor component.

The turbine 42 is positioned and configured to be driven by refrigerant discharged from the discharge end 70 of the first passageway 62 when the first nozzle 24 is connected to the energy recovery apparatus sub-assembly 22, and to be driven by refrigerant discharged from the discharge end 82 of the second passageway 74 when the second nozzle 26 is connected to the energy recovery apparatus sub-assembly. The discharge port 58 is adapted to permit refrigerant to flow out of the energy recovery apparatus 24. The discharge port 58 of the energy recovery apparatus 24 is downstream of the turbine 42.

The first necked-down region 64 has a downstream end 64 a and the second necked-down region 76 has a downstream end 76 a. The downstream end 64 a of the first necked-down region 64 has a cross-sectional area less than a cross-sectional area of the intake opening of the first nozzle 24. The downstream end 76 a of the second necked-down region 76 has a cross-sectional area less than a cross-sectional area of the intake opening of the second nozzle 26. Preferably, each necked-down region 64, 76 gradually decreases in cross-sectional area toward its downstream end 64 a, 76 a, respectively. Alternatively, each necked-down region may abruptly decrease in cross-sectional area without departing from the scope of the present invention.

Preferably, the first and second passageways 62, 74 are each in the form of a cylindrical bore, but can be of other shapes without departing from the scope of this invention. In the present embodiment, the downstream cross-section 78 of the first passageway 62 is adjacent the discharge (downstream) end 70 of the first passageway 62, and the downstream cross-section 80 of the second passageway 74 is adjacent the discharge (downstream) end 82 of the second passageway 74.

The downstream cross-section 78 of the first passageway 62 has a first effective diameter defined as (4A1/π)^(1/2), where A1 is the cross-sectional area of the first passageway 62 at the downstream cross-section 78 of the first passageway. The downstream cross-section 80 of the second passageway 74 has a second effective diameter defined as (4A2/π)^(1/2), where A2 is the cross-sectional area of the second passageway 74 at the downstream cross-section 80 of the second passageway 74. As used herein, the cross-sectional area is the planar area generally perpendicular to the intended direction of flow at the given point in the first or second passageway, e.g., at the downstream cross-section 68 or 80 of the first or second passageway. The cross section of each of the first and second passageways 62, 74 at any point along the first or second passageway lengths, respectively, is preferably circular, but it is to be understood that other cross-sectional shapes may be employed without departing from this invention. Preferably, the cross-sectional area of the first passageway 62 at the downstream cross-section 78 of the first passageway is not greater than the cross-sectional area of the first passageway at any point along the first passageway length, and the cross-sectional area of the second passageway 74 at the downstream cross-section 80 of the second passageway is not greater than the cross-sectional area of the second passageway at any point along the second passageway length. The first passageway 62 may have a generally constant cross-sectional area along the first passageway length, and the second passageway 74 may have a generally constant cross-sectional area along the second passageway length. Alternatively, the first passageway 62 may converge as it extends toward the discharge end of the first passageway, and the second passageway 74 may converge as it extends toward the discharge end of the second passageway.

Preferably, the first passageway length of the first passageway is at least five times the first effective diameter, and more preferably at least seven and one-half times the first effective diameter, and more preferably at least ten times the first effective diameter, and even more preferably at least twelve and one-half times the first effective diameter. The second passageway length of the second passageway 74 is preferably at least five times the second effective diameter, and more preferably at least seven and one-half times the second effective diameter, and more preferably at least ten times the second effective diameter, and even more preferably at least twelve and one-half times the second effective diameter.

Referring again to FIGS. 1 and 7, the housing 40 of the energy recovery apparatus sub-assembly 22 includes a nozzle receiving opening 84. The first nozzle body 24 a is shaped and configured for being operably connected to the housing 40 in a position in which the first passageway 62 aligns with the nozzle receiving opening 84. The first nozzle body 24 a may include a threaded end for a threaded connection to the housing, or the first nozzle body may be connectable to the housing via any other conventional means. The second nozzle body 26 a is shaped and configured for being operably connected to the housing 40 in a position in which the second passageway 74 aligns with the nozzle receiving opening 84. The second nozzle body 26 a may include a threaded end for a threaded connection to the housing, or the second nozzle body may be connectable to the housing via any other conventional means. An adapter 86 and adapter nut 88 may be supplied for operatively connecting a refrigerant line (not shown) to either the first or second nozzle 24, 26. The size or shape of the second passageway 74 of the second nozzle 26 is different from the size or shape of the first passageway 62 of the first nozzle 24 to enable a user to selectively choose one of the other of the nozzles for operable connection to the housing 40. The first nozzle 24 may be of a size and shape for use in one size or type of refrigeration system (e.g., a four ton system), and the second nozzle 26 may be of a size and shape for use in another size or type of refrigeration system (e.g., a five ton system). Thus, a user may make the choice that accomplishes the better refrigerant flow characteristics when the passageway of the chosen nozzle is in the flow path of the refrigeration system.

The first nozzle 24 is preferably adapted and configured such that the liquid component of the refrigerant discharged from the discharge end 70 of the first passageway 62 has a velocity that is at least 60% that of the velocity of the vapor component of the refrigerant discharged from the discharge end 70 of the first passageway and more preferably has a velocity that is at least 70% of the velocity of the vapor component of the refrigerant discharged from the discharge end of the first passageway. Likewise, the second nozzle 26 is preferably adapted and configured such that the liquid component of the refrigerant discharged from the discharge end 82 of the second passageway 74 has a velocity that is at least 60% that of the velocity of the vapor component of the refrigerant discharged from the discharge end 82 of the second passageway and more preferably has a velocity that is at least 70% of the velocity of the vapor component of the refrigerant discharged from the discharge end 82 of the second passageway. If the refrigerant is expanded too rapidly in the nozzle (e.g., if the passageway is insufficiently long), then the velocity of the liquid component will be insufficient to impart the desired force on the turbine blades 50.

Preferably, the first nozzle 24 is adapted and configured to discharge the liquid component of the refrigerant from the discharge end 70 of the first passageway 62 at a velocity of at least about 190 feet per second (58 m/s) and more preferably at a velocity of at least about 220 feet/second (67 m/s). Preferably the second nozzle 26 is adapted and configured to discharge the liquid component of the refrigerant from the discharge end 82 of the second passageway 74 at a velocity of at least about 190 feet per second (58 m/s) and more preferably at a velocity of at least about 220 feet/second (67 m/s). Also, the passageways should not be made excessively long such that the pressure of the refrigerant is too low to match the pressure requirements of the first heat exchanger.

Preferably, each of the nozzles 24, 26 is shaped and configured such that refrigerant entering the nozzle at X % liquid and (100−X) % vapor, by mass, is expanded as it passes through the nozzle and is discharged from the discharge end of the corresponding passageway in a liquid-vapor state with a liquid component that is at most at (X−5)% and a vapor component that is at least (105−X) %, by mass. One of ordinary skill in the art will appreciate that “X”, as used herein, is typically the number 100, but could be a number somewhat less than 100.

In operation, the energy recovery apparatus sub-assembly 22, and the first and second nozzles 24, 26 may be provided to a person. The person may be a manufacturer of refrigeration equipment, or a person downstream of the manufacturer. The manufacturer of refrigeration equipment may sell an indoor unit with the energy recovery apparatus sub-assembly 22 and the first nozzle 24 connected to the indoor unit. The second nozzle 26 and perhaps additional nozzles may be packed in an accessory kit and, along with the assemblage of the indoor unit and the recovery apparatus sub assembly 22 and the first nozzle, may be provided to a user. Because the different nozzles provide different flow characteristics, having the different nozzles enable the user to match the indoor unit with a different capacity outdoor unit. Written instructions, or other indicia may also be provided to indicate to the user that the second nozzle may be connected to the energy recovery apparatus sub-assembly 22.

As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. For example, although the energy recovery apparatus sub-assembly is described and shown as having one nozzle receiving opening and being adapted for receiving only one nozzle at a time, it is to be understood that the present invention also applies to a multi-nozzle energy recovery apparatus. A multi-nozzle energy recovery apparatus in accordance with the present application is similar to the multi-nozzle energy recovery apparatus disclosed in co-pending U.S. patent application Ser. No. 14/179,899 filed Feb. 13, 2014 (incorporated herein by reference), except the nozzles are changeable nozzles, and more than two nozzles would be included to provide changeability. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.

It should also be understood that when introducing elements of the present invention in the claims or in the above description of exemplary embodiments of the invention, the terms “comprising,” “including,” and “having” are intended to be open-ended and mean that there may be additional elements other than the listed elements. Additionally, the term “portion” should be construed as meaning some or all of the item or element that it qualifies. Moreover, use of identifiers such as first, second, and third should not be construed in a manner imposing any relative position or time sequence between limitations. Additionally, the term person may be an individual or an entity, such as a corporation or partnership. Still further, the order in which the steps of any method claim that follows are presented should not be construed in a manner limiting the order in which such steps must be performed. 

What is claimed is:
 1. An energy recovery apparatus adapted for use in a refrigeration system, the refrigeration system comprising a first heat exchanger, a compressor and a second heat exchanger, the refrigeration system being configured to circulate refrigerant along a flow path such that the refrigerant flows from the first heat exchanger to the compressor, and from the compressor to the second heat exchanger, and from the second heat exchanger to the first heat exchanger, the energy recovery apparatus being adapted and configured to be in the flow path operatively between the second heat exchanger and the first heat exchanger, the energy recovery apparatus comprising: a housing having a nozzle receiving opening and a discharge port; a turbine within the housing, the turbine being adapted to be driven by refrigerant passing through the nozzle receiving opening; a first nozzle comprising a first nozzle body having a first conduit region, the first conduit region defining a first passageway, the first passageway having a discharge end, the first nozzle being operably connectable to the housing in a position in which the first passageway aligns with the nozzle receiving opening, the first nozzle being adapted and configured to expand refrigerant passing through the first nozzle and to discharge the refrigerant from the discharge end of the first passageway in a liquid-vapor state with a liquid component and a vapor component; a second nozzle comprising a second nozzle body having a second conduit region, the second conduit region defining a second passageway, the second passageway having a discharge end, the second nozzle being operably connectable to the housing in a position in which the second passageway aligns with the nozzle receiving opening, the second nozzle being adapted and configured to expand refrigerant passing through the second nozzle and to discharge the refrigerant from the discharge end of the second passageway in a liquid-vapor state with a liquid component and a vapor component; the size or shape of the second passageway of the second nozzle being different from the size or shape of the first passageway of the first nozzle to enable a user to selectively choose one of the first and second nozzles for operable connection to the housing, whereby the user may make the choice that accomplishes the better refrigerant flow characteristics when the passageway of the chosen nozzle is in the flow path of the refrigeration system; the discharge port being adapted to permit refrigerant to flow out of the energy recovery apparatus, the discharge port of the energy recovery apparatus being downstream of the turbine.
 2. An energy recovery apparatus as set forth in claim 1 further comprising a generator coupled to the turbine and adapted to be driven by the turbine, the generator being configured to produce electricity as a result of the turbine being driven by refrigerant passing through the nozzle receiving opening.
 3. An energy recovery apparatus as set forth in claim 2 wherein the generator is within the housing.
 4. An energy recovery apparatus as set forth in claim 3 wherein the housing, the turbine, and the generator are arranged and configured such that refrigerant passing through the energy recovery apparatus cools and lubricates the generator.
 5. An energy recovery apparatus as set forth in claim 3 wherein each of the first and second passageways has an upstream cross-section, a downstream cross-section, and a passageway length extending from the upstream cross-section to the downstream cross-section, the downstream cross-section of the first passageway being closer to the discharge end of the first passageway than to the upstream cross-section of the first passageway, the downstream cross-section of the second passageway being closer to the discharge end of the second passageway than to the upstream cross-section of the second passageway, the cross-sectional area of the first passageway at the downstream cross-section of the first passageway being not greater than the cross-sectional area of the first passageway at any point along the passageway length of the first passageway, the cross-sectional area of the second passageway at the downstream cross-section of the second passageway being not greater than the cross-sectional area of the second passageway at any point along the passageway length of the second passageway.
 6. An energy recovery apparatus as set forth in claim 5 wherein the downstream cross-section of the first passageway has a first effective diameter, and wherein the downstream cross-section of the second passageway has a second effective diameter, the first effective diameter being defined as (4A₁/π)^(1/2), where A₁ is the cross-sectional area of the first passageway at the downstream cross-section of the first passageway, the second effective diameter being defined as (4A₂/π)^(1/2), where A₂ is the cross-sectional area of the second passageway at the downstream cross-section of the second passageway, the passageway length of the first passageway being at least five times the first effective diameter, the passageway length of the second passageway being at least five times the second effective diameter.
 7. An energy recovery apparatus as set forth in claim 6 wherein the passageway length of the first passageway is at least seven and one-half times the first effective diameter, and the passageway length of the second passageway is at least seven and one-half times the second effective diameter.
 8. An energy recovery apparatus as set forth in claim 6 wherein the passageway length of the first passageway is at least ten times the first effective diameter, and the passageway length of the second passageway is at least ten times the second effective diameter.
 9. An energy recovery apparatus as set forth in claim 6 wherein the passageway length of the first passageway is at least twelve and one-half times the first effective diameter, and the passageway length of the second passageway is at least twelve and one-half the second effective diameter.
 10. An energy recovery apparatus as set forth in claim 5 wherein the first passageway has a generally constant cross-sectional area along the passageway length of the first passageway, and wherein the second passageway has a generally constant cross-sectional area along the passageway length of the second passageway.
 11. An energy recovery apparatus as set forth in claim 10 wherein the cross-sectional area of the first passageway is different from the cross-sectional area of the second passageway.
 12. An energy recovery apparatus as set forth in claim 5 wherein the first nozzle further comprises a first necked down-region, the first passageway being downstream of the first necked-down region, the first necked-down region being adapted to constitute a portion of the flow path when the refrigeration system is operated in the first mode, and wherein the second nozzle further comprises a second necked down-region, the second passageway being downstream of the second necked-down region, the second necked-down region being adapted to constitute a portion of the flow path when the refrigeration system is operated in the second mode.
 13. An energy recovery apparatus as set forth in claim 5 wherein at least a portion of the first passageway converges as it extends toward the discharge end of the first passageway, and wherein at least a portion of the second passageway converges as it extends toward the discharge end of the second passageway.
 14. An energy recovery apparatus as set forth in claim 5 wherein the first heat exchanger comprises an evaporator and the second heat exchanger comprises a condenser.
 15. A method comprising: providing an energy recovery apparatus sub-assembly to a person, the energy recovery apparatus sub-assembly being adapted for use in a refrigeration system, the refrigeration system comprising a first heat exchanger, a compressor and a second heat exchanger, the refrigeration system being configured to circulate refrigerant along a flow path such that the refrigerant flows from the first heat exchanger to the compressor, and from the compressor to the second heat exchanger, and from the second heat exchanger to the first heat exchanger, the energy recovery apparatus sub-assembly being adapted and configured to be in the flow path operatively between the second heat exchanger and the first heat exchanger, the energy recovery apparatus sub-assembly comprising a housing, a turbine, and a generator, the housing having a nozzle receiving opening and a discharge port, the turbine and the generator being within the housing, the turbine being adapted to be driven by refrigerant passing through the nozzle receiving opening, the generator being coupled to the turbine and adapted to be driven by the turbine, the generator being configured to produce electricity as a result of the turbine being driven by refrigerant passing through the nozzle receiving opening, the discharge port being adapted to permit refrigerant to flow out of the energy recovery apparatus, the discharge port of the energy recovery apparatus being downstream of the turbine; providing a first nozzle to said person, the first nozzle comprising a first nozzle body having a first conduit region, the first conduit region defining a first passageway, the first passageway having a discharge end, the first nozzle being operably connectable to the housing in a position in which the first passageway aligns with the nozzle receiving opening, the first nozzle being adapted and configured to expand refrigerant passing through the first nozzle and to discharge the refrigerant from the discharge end of the first passageway in a liquid-vapor state with a liquid component and a vapor component; providing a second nozzle to said person, the second nozzle comprising a second nozzle body having a second conduit region, the second conduit region defining a second passageway, the second passageway having a discharge end, the second nozzle being operably connectable to the housing in a position in which the second passageway aligns with the nozzle receiving opening, the second nozzle being adapted and configured to expand refrigerant passing through the second nozzle and to discharge the refrigerant from the discharge end of the second passageway in a liquid-vapor state with a liquid component and a vapor component, the size or shape of the second passageway of the second nozzle being different from the size or shape of the first passageway of the first nozzle to enable a user to selectively choose one of the first and second nozzles for operable connection to the housing, whereby the user may make the choice that accomplishes the better refrigerant flow characteristics when the passageway of the chosen nozzle is in the flow path of the refrigeration system.
 16. A method as set forth in claim 15 wherein the first nozzle is connected to the energy recovery apparatus sub-assembly when the energy recovery apparatus sub-assembly and the first nozzle are provided to said person.
 17. A method as set forth in claim 16 further comprising providing written indicia to said person indicating that a user may connect the second nozzle to the energy recovery apparatus sub-assembly.
 18. A method as set forth in claim 15 wherein each of the first and second passageways has an upstream cross-section, a downstream cross-section, and a passageway length extending from the upstream cross-section to the downstream cross-section, the downstream cross-section of the first passageway being closer to the discharge end of the first passageway than to the upstream cross-section of the first passageway, the downstream cross-section of the second passageway being closer to the discharge end of the second passageway than to the upstream cross-section of the second passageway, the cross-sectional area of the first passageway at the downstream cross-section of the first passageway being not greater than the cross-sectional area of the first passageway at any point along the passageway length of the first passageway, the cross-sectional area of the second passageway at the downstream cross-section of the second passageway being not greater than the cross-sectional area of the second passageway at any point along the passageway length of the second passageway.
 19. A method as set forth in claim 18 wherein the downstream cross-section of the first passageway has a first effective diameter, and wherein the downstream cross-section of the second passageway has a second effective diameter, the first effective diameter being defined as (4A₁/π)^(1/2), where A₁ is the cross-sectional area of the first passageway at the downstream cross-section of the first passageway, the second effective diameter being defined as (4A₂/π)^(1/2), where A₂ is the cross-sectional area of the second passageway at the downstream cross-section of the second passageway, the passageway length of the first passageway being at least five times the first effective diameter, the passageway length of the second passageway being at least five times the second effective diameter, the cross-sectional area of the first passageway being different from the cross-sectional area of the second passageway.
 20. A method as set forth in claim 19 wherein the first heat exchanger comprises an evaporator and the second heat exchanger comprises a condenser. 